Process of precipitating materials from solutions.



D. BOSQUI. PRDGESS OP PREGPI-TATING MATERIALS PROM SOLUTIONS.

APIVJLIOATION ILED DB0.9,1911y Patented Jan.7,1913.

2 SHBETSSHBET l.

D. BOSQUI. PROCESS OF PREGIPITATING MATERIALS PROM SOLUTIONS.

APPLICATION FILED 1120.9, 1911.

l @49569. Patented Jan. 7, 1913.

2 SHEETS-SHEET 2.

l/vx/E/voR DANIEL Bosgm.

HIS ATTORNEYS.

sas PATENT OFFICE.

DANIEL BOSQ'I,

F MONAHAN, WASHINGTON, ASSIG-NOR TO CAL COMPANY, A CORPORATION OFCALIFORNIA.

MERRILL METALLURGI- OF PRECPITATLNG MATERIALS FROM SOLUTIONS.

Specncaton of Letters Patent.

Patented J an. 7,1913.

Application filed December 9,1911. Serial No. 664,745.

Precipitating Materials from Solutions, of

which the following is a specification.` This application relates to animproved 'process of recovering valuable metals from solution andparticularly metals from hydrometallurgical solutions.

In practice, metallic zinc-bearing materials or other metalliferousprecipitants have heretofore been used to precipitate metalsv fromcyanid solutions and the most practical results have been obtained byadding such inetalliferous precipitant to the solution in a closedreceptacle or in such manner that the air has been excluded from themixture of solution, precipitant and precipitate and subsequentlyconducting the mixture without additional agitation through a. filter.By vthis method, however it is difficult to adjust orf prolong thecontact between the solution and precipitant in accordance ywith therequirements of .solutions low in cyanid content.

in practice Zinoiferous precipitants have been used to precipitatecyanid solutions in the following ways. Said precipitants have beenvadded to the solution and the mixture agitated usually by compressedair, and occasionally by mechanical stirrers. p In either event anentrainment 'of material amounts of the oxygen of the-air has result-ed,which oxygen is a serious deterrent to the most ecient precipitation,which is a reducing reaction. For the purpose of best obviating thisoxygenation, metalliferous precipitants have been added to the solutionin a closed circuit andthe mixture conducted without rest, withoutexposure to the atmosphere,l

and without prolonged agitation to a closed filter. ln the lattermethod, however, it is difficult to adjust or prolong thecont'actbetween the solution and precipitant, which prolonged and adjustablecontact is desirable when the solutions are low in strength or otherwisefeeble in activity toward the precipitant. v

In the presentprooess the time of contact of the precipitant with thesolution may be results, depending upon the circumstances of operation,and the precipitant may be reclroulated through t-he solution so that itis prolonged and regulated to obtain the bestV continually brought intoeffective contact with the solution without subjecting the mixture ofsolution, precipitant and precipitate to the ,deleterious effects ofentrained air, as is the case when the surface of the mixture ismarkedly agitated by means of mechanical agitators or when the mixtureis agitated by compressed air.

The object of the invention is to provide an improved method ofprecipitating and recovering valuable metals from solution andparticularly metals fromhydro-metallurgical solutions.

The process possesses other advantageous features, which with theforegoing will be set forth at length in the following description,where I shall. more fully describe the process and outline in full thepreferred form of apparatus for carrying out said process.

The preferred-form of apparatus is illustrated in the drawingsaccompanying and forming part of the present specification.

The novelty of the invention will be included in the claims succeedingsaid description. From this it will 'be apparent that I do not restrictmyself to the showing made by said drawings and description, as I mayadopt many variations within the scope of my invention. as expressedV insaid claims.

Referring to the drawings,- which disclose the preferred form ofapparatus for carrying out my process z-Figure l is a side elevation ofthe apparatus with ,the receiving tanks in vertical section, one ofsaid/tanks being shown filled with solution and its outlet valve openedfor the discharge thereof, the companion tank being partly filled withliquid and its outlet valve closed. Fig. 2 is a to-p or plan view of theapparatus as shown in Fig. 1. Fig. 3 is a side elevation of the zincdust or precipitant receptacle illustrating the slide arm carrying thecutter blades and the tiltingI lever for 'actuating the slide arm. Fig.4 isa detail plan view of the zinc dustreceptacle and the slide armcarrying the cutter blades movable within the Zinc dust receptacle andcontrolling the discharge therefrom. Fig. 5 is a fragmentary sectionalviewvof one of the arms of the rotary agiythen agitated 1n such lowingthe mixture therein ceiving tanks. o

In the drawings I have illustrated an apparatus for continuously andautomatically carrying on the process by the use of a plurality ofreceiving tanks, but it is understood that the process may be carried onintermittent-ly or continuously by the use of one tank when desired.

The cyanid solution to be treated is con-l ducted to the tank and at acertain predetermined point in' the filling thereof, deter- `.mined bythe rate of the rise of the solution in the tank, and thecharacteristics of .the solution, a predetermined amount of precipitantis added to the solution. The mixture of solution, precipitant andprecipitate, is manner that the upper or exposed surfacel thereofremains substantially placid and no air is ent-rained in the solution.The solution still flowing into the tank inthe preferred form ofapparatus shown is deposited in such manner that the.

surface of the solution is not markedly disturbed. The only contact ofthe mixture with air that possibly takes place is through the surfaceexposure, which, on account of the quiescent state of the surface is anegligible quantity. As the cyanid solution continues to How into thetank, the level of the mixture of solution, precipitant and precipitatetherein rises, and at a determined height, the supply of solution is cutoff'and the discharge valve of the tank opened, al-

to be conducted to the filter in which the precipitates are removed. 1nthe apparatus' shown in the accompanying drawings this process is.carried on continuously and automatically.

The mechanism' for controlling the flow of the cyanid solution andcutting olf the supply thereof, regulating the feed of the zinc dust,and governing the discharge of the mixture is identical in connectionwith each .of the receiving tanks, likewise the means employed for.maintaining mixture in an agitated condition.

The numerals 1 and 2 are employed to designate the receiving tankswithin which the cyanid alternately. delivered, the cyanid solutionbeing delivered to the said tanks respectively by means Vof a Vat itscenter on der receives the solution the feed pipe 5;

the journals et, which launto be treated from `Attached to the ends ofthe launder 3 are vformed preferably` conducto-rs or chutes 3 of canvasor other flexible material, which convey the solution from the laundertothe tank. -These conductors 3 extend downward -to a. position adjacentto the lower surface of the floats 6-6 so -that'the lower ends thereofare immersed inthe solution 'arrangement allows the .free end of which,

solution to be precipitated istilting la-under 3, supported ing onv bo'x-17 and the distanceA that the' cutter in the tank before the iioat israised. This posited in the tank without markedly diS- turbing thesurface of the mixture therein, after the precipitanthas been added. Bymaintaining a substantially placid surface, no air is entrained in themixture and the detrimental effects thereof are obviated.

Referring now more particularly to tank 1, as the solution deliveredtherein by the launder 3 approaches the filling point thereof,predetermined by the length of contact required for the zinc dust to besupplied thereto, the solution acts against the float 6 suspended withinsaid tank and raises the same, the stem 7 of which float works through aguideS clamped to the inner end of the tilting lever 9. This leverconsists of a tubular rod or pipe, partly filled with quicksilver andsupported centrally o-n the journal 10. To the stem 7 are secured aboveand below the guide S the collars 11, the lower`one of which7 on theupward movement of the float'raises the inner end of the pivoted ortilting lever 9. said lever and projecting upwardly centrally therefromis a depending on the upward and downward movement of the float G,engages with a pin 13 projecting laterally from a horizontally siidablearm ,1% and moves the same inwardly and outwardly. This slide armcarries the: cutter blades 15 and 16, which move within the Zinc feedboX or receptacle 17 from opposite sides, working within milled groovesin said box. The cutter blades are separated or spacedapart and theinner end of the bladelG overlaps the inner end of the blade 15 for aslight distance, about one-half an inch, so that when the blade 16 makesits return stroke from within the box 17, the same moving in unison withthe bladeil no Zinc dust feeds out of the box. .As the inner end of thelever 9 is 'carried past the horizontal bythe uprise of the ilo-at 6,the Quicksilver contained therein flows to the oppositeend of the tubelever 9. and the forked arm 12, attached to the said lever impingesonthe pin or stud 13 and shifts the arm 14 to move the cutter 16 withinthe feed box 17 and the lcutter 15 from within' the same, allowing thezinc dust to drop within the tank 1, the amount or charge of the -Z'incdust dependthe inside measurement of the feed The blades 15 and 16 arespaced apart.

vzinc dust is preferably conveyed from the feed .box 17 to the solution1n the tank 'through a canvas chute 36 which is formed Vof-such lengththat the lower end thereof lies below the surface of the solution,before the Zinc dust is added to the solution.

After the charge' of zinc dust hasbeen dis charged within the tank 1,the' mixture con- Attached to the 'solution to be deforked arm 1Q, the

tinuing'to rise therein actuates the float 1S and through the connectionof its stem 19 withV the launder 3, raises such end of the said` tiltinglaunder, and as the same is carricd above the horizontal position,elevates such endv o-f the pipe 20, containing quicksilver, which pipe1s connected to the v oted` launder 3 at each end by the. supports 21.During this movement of the tube y the quicksilver contained thereinl isshifted toward the lowered endthereof, while at Y the same time theinner end of the lever 22 is raised and the outer end thereof depressed,the said lever being fulcrumed `to the swinging link 23, which allowsfor the arc made by" the-launder during its tilting movement. iAs t-heinner end of theilever 22 is raised orfelevated, its outer end is.depressed, which being connected to the vertl- `cally movable rod 2 4actuates the saine to operate the valve 'controlling theoutow of fthe'-inixture `of solution, precipltant and precipitate; from within thetank 1. The

lower endl of the r'od 24 works through the slotted lever 25, which isacted on by the collars 26 adjustably secured 'to said rod above andbelow the lever 25. y is fulcrumed at 27 and the outer end thereof isconnected to a stem 28 projectingfrom the controlling valve 29 situa-tedwithin the out-let pipe 30, consequently when the up percollar26 actsagainst the inner end lof the .lever 25 ,on jthe downward movementthereof,- the saine is carried therewith and Lits outer end thrownupwardly,drawing therewith the stein 2S and raising or unseat- ,ing thevalve 29 to permitof the outflow ofv the-mixture from within the tank 1through the: outlet pipe- 30, permitting the mixture torun to the usualfiltering medium 37.

The zinc feeder having been operated by the float 6 and subsequently thefloat 18'having operated the tilting or swinging launder i 3and at thesame time operated the valve' v29 for allowing the escape of the mixturefrom tank 1,.the gold and silver bearing .so-

llution will now be flowing from the launder 3 into the tank 2ltheoutlet valve 29 of which is closed. The operation of the working partsfor said tank controlling the shiftingof theswinging or tilting launder3 the feed of zinc dust into the solution flow-y inginto the said tankand'the ,operation with tankl, that is as the float d is acted Aon b-ythe inflowing 'solution the same is raised and through its ste=1n-"7`woirking through a guide 8 clamped to a't-ilting le- 'ver 9 consisting'of a tube partly filled with quicksiluer, the feed of zinc dust isdelivered to the'solution flowing intothegsaid tank 2.' Thelever 9 issupported centrally on'the journal 10', and to the' stem 7 above andbelow the guide 8 the collars 11 are se-xcured.

. To the lever 9"isV securedaJ projecting` The lever 25 'raising andlowerin the inner end thereof i forked arm`12-, which acts against orstud 13 lprojecting from the horizont-ally slidable arm 14', carryingthe cutterv blades horizontal arm which carrying therewith the .tube 20shifts the qucksilver contained therein to the opposite end thereon'. atthe same time the movement of the launder raising the inner end of thelever 22', `ful-4 crumed `at 23 a-nd depressing the outer endthereof,'forcin downwardly` thel rod24, which acts to epress the innerend ofthe lever 2 5 fulcrumed at 27,', Land' raise the outerlend-thereof, liftingfthe steml 28 vto unseatjthe valve 29" and permitthe outow of thel ymixture through the outlet pipe30 On thel rod 24,above vand below the lever 25 are secured the collarsr26, which act`against the free end of the lever 25 for in accordance with tie movementofthe actuatingrod 24.v The lowerend offeachf ac;

tuat-ing rod 2ay and 24: works' through a 'guide31`secured to andprojecting from vthe, frame 32 .of the appara-tus, by the upper framepieces of which the tiltingr'neinb'ers of the apparatus are supported. j

It will be understood that as the actuating mechanism for one tank isthrown 'into-o eration by the filling of the saine with cyamd solutionto be precipitated the mixture contained' in the lcompanion tank lis'being y`withdrawn, and that as the raising of 'the floats in one tankshifts the positionof the operating mechanism for .one tank, the lower`ring of the float-'s inthe companion .tanks actto `place the operatingmechanism ina reverse'pos'ition to that assumed by the correspendingparts of thel tank being lille'd solution for precipitation. j

In each tankl s located an agitator 33,' leach being carried by avertical {shaft-34.

The tubular 'radial arms ofthe a-gitatorare provided with dependinginclined nipples or nozzles 33,and each agitator is connected by a pipe34 to a centrifugal pump35, which takesliquid from withinthe'tank bylmeans of a suction pipe 35".' The liquid thus drawn from the tankv isforced by the centrifugal pump 35 backiinto the agitator 33 throughthedis'charge pipe 34, the presl 'sure of the1 liqlfiidrthus'forced into"the vagitatorsescaples'@through; .the nozzles 33', vcausing `theagitators to-begfrotated-at a suit-able 'speed The disposition ofthevnozzles .orV

ist

. the recipitant is deposited l lmm.

nipples 33 relative to the tubular radial l subjecting the mixturetothe` oxidizing ef-n arms' of theV agitators is such, that at eachcomplete revolution of the agitators the discharge from the nozzles ornipples, which arearranged at an angle tothe bottom of the links, sweepsthe ent-ire'surface of the bottom of the tanks. y

The disturbance .of the mixture caused by the agitator is such that'theA upper surface ,thereof is not affected thereby and remains placidafter it has. reached the level at which in the solution.

'T e jets of liquid striking the bottom`ot the tank prevent anysettlement of the pre'- cipitates. Through the agency of the agitatorsanagitation of the solution is maintained that brings the. zinc dustparticles the pregnant solution into intimate contact, while thecircular motion ofthe tubular arms-gives a rotary movement to thesolution,.and the'jets ,ofldischarge create an up- 'ward ,current ofsolution, .alltendin to produce perfect'agitatio'n and prolonge contactbetween solution and precipitant and at the saictime admitting orentraining no air to the solution.v The only contact with air that canpossibly take place. is through the sur-V face exposure vo f"--tl ie-solution which is a n ligible quantity.

. en the zine dust isaddedoto' the S0111! tion, it sinks to thebottom'where itis stirred ais vthe tank with the solution passingvlthrough the pump upV and mixed vwith the solution by the agi- -tators.A portion of the zincdust and articularly the heavier and largerparticles thereof which have a greater tendency to settle to the bottomare continuously drawn y and are discharged into the-solution 1n thetank from the agitator nipples.-' ff1 `his re-circulation of the'precipitant'ca'l'ises an intimate recurring and pro-A longed contactwith the pregnant 'solution and assists in producing a substantiallycomplete and perfect precipitation. Furthermore,by this re-circulation,the size of these `heavier and coarser particles is reduced by contactwith the solution and a correspondingly greateramount of precious metalpre- By -1 the use of the described apparatus there lisa positive feedof a predetermined quantity of vzinc dust to a given quantity of beprecipitated, the flow of the solution for a single charge of the zincdust therefor being automatically controlled, al

f positive time contact for the `zinc dust with the solutionv isprovided, which may be varied according to the requirements of thesolution to be precipitated, and in individual cases may thereafter befixed. At the same time the mixture is maintained in a continuousagitated condition during the entire operation of precipitation andtheprecipitant ishre-circulated through the mixture without f and silvertherefrom,

fects of entrained air.

By` predetermined in this specification is meant predetermined in apractical sense as metallurgically applied to the operat-ion ofreduction works. For instance a predetermined amount of zinc dust meansthe amount which has been found by previous operations tobe sufficientto best meet the re# quirements of the general operation of the plant.Similarly predetermined time ofl contact means that period whichexperience has demonstrated gives the best average results, all thingsconsidered, for the economic` and eflicient operation of the works.

I claim: v

1. The continuous method of treating cyanid solution for theprecipitation of gold which consists in distributing the supply ofsolution alternately between a plurality of receiving vessels, deliverinalternately to said vessels, during thelling thereof with solution, apredetermined charge of zinc dust, withdrawing the treated solution fromone vessel during the filling of theother vessel with the solution to betreated.

2. The continuous method of treating A cyanid solution for theprecipitation of material therefrom which consists in distributing thesupplyl of solution alternately between a plurality of receivingvessels, de-

livering alternately to said vessels during the iilling thereof withsolution, a predetermined c-harge of a precipitant, withdrawing thetreatedsolution from one vessel during the filling of the other vesselwith the solution to be treated.

3. The process of precipitating materials from solution which consistsin adding a predetermined amount of a precipitant to a predeterminedamount of solution and agitating'the mixture for 'a variablepredetermined time,- the placidity of the exposed surface thereof.

,4. The process of precipitating materials from solution which consistsin automatically adding a predetermined amount of a precipitant tosolution and agitating ythe mixture for a variable predetermined timewithout lmaterially disturbing the placidity of ,the exposed sur'face.,l

5. The continuous method of treating cyanid solution for theprecipitation ofv without4 materially disturbing a predetermined amountof at a predetermined time in the filling. thereof, a. predeterminedcharge of precipitant, agitating the mixture and withdrawing the samefrom one vessel during the iilling of another with the solution to beprecipitated. y

6. The piocess of precipitating materiai from its solution whichconsists in adding a preciptant to seid solution and ire-circuiatiig'the' precipitziiit through the solution.,

7. The process of precipitating moitei'iai from its solution whichconsists .in adding a pirecipitan; thereto, and'agitatiiig the ture byrecircuiatiiig a portion of the p cipitant therethrough.

v 8. The process oi' precipitating materifd. from its solution whichconsists in a'c'idiigg a precipitant thereto, git'atiiig the mixture fora predetermined time Withc-ut eilt-mining; any air therein, andcontinuait? rie-circulating Some of the piecipient through the solutionduring said time.

9. The process of ccipitatiiagg i'iiateiiai from solution Which consistsin agitating the mixture oi soiutioii ind precipita-nt by iecirculatingrthe pfecipitaiit therethiough Without eiitiaiiiing any air therein.

10. The process of precipitating material from :i solution whichconsists in afg ting" the mixtiie'of solution and. precipitaiit byPci-circulating the same tiiioiigh the contain ing receptacle Withouteitaiiiiig air.

' 11. The process of precipitating iiiaei'iei from a' solution whichconsists in agitzitiiig; the mixture. of solution and piecipitant 310 bycontinuously ive-circulating the same contaiiiiiiw receptacle'Witlidifswin same ifi/gom the.

feceptacie and' c iive/ through e c! circuit be, l ceptacie and a'jy'cenduccing' tin. 'from the iecc'ptzicie through :i cioe all of said'feos loeing continuous Mid out entrain] air.

1S. The piiocess of recovering; ,egoid siivci cyanid solutions Witchconsists m Giese

